Voice biometric engines work by recording an “utterance” spoken by a user and creating a voiceprint, known in the industry as a “template.” This act of collecting an utterance and creating a template is called a user “enrollment.” To subsequently authenticate a user, another utterance is recorded and compared to the template. This act of comparing an utterance to a template is called a “verification” or “authentication.”
The method used to create a template differs among various biometric engines. Commercial voice biometric engines fall, however, into two general categories: text-dependent and text-independent. With text-dependent engines, utterances may be less than a second in length, but a user must repeat the exact words required by the engine for authentication. With text-independent engines, however, enrollment requires upwards of 30 seconds of audio, but thereafter the user can say anything to be authenticated.